Monitoring adequacy of ventilation by capnometry during thoracotomy in dogs.
OBJECTIVE
To determine whether end-tidal partial pressure of carbon dioxide (PETCO2) was a reliable estimate of PaCO2 in dogs undergoing thoracotomy.


METHODS
Case series.


METHODS
18 dogs that underwent thoracotomy.


METHODS
PaCO2 and PETCO2 were measured shortly after induction of anesthesia, while dogs were breathing spontaneously; 5 minutes prior to initial skin incision, while dogs were receiving intermittent positive-pressure ventilation (IPPV); 5, 30, and 60 minutes after the thoracic cavity was opened, while dogs were receiving IPPV; and after the thoracic cavity was closed and evacuated, when dogs were again breathing spontaneously. For each period, arterial-end-tidal difference in partial pressure of carbon dioxide (PaCO2-PETCO2) was compared with PaCO2-PETCO2 for the preceding period.


RESULTS
Significant changes in PaCO2-PETCO2 from one period to the next were not detected except when values obtained 5 minutes after the thoracic cavity was opened were compared with values obtained 5 minutes before incision. The PaCO2-PETCO2 was not constant for individual dogs.


CONCLUSIONS
PETCO2 was not a reliable indicator of adequacy of ventilation during thoracotomy in these dogs, because it differed greatly from PaCO2, and PaCO2-PETCO2 was not consistent.
Wagner
A E
AE
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
Gaynor
J S
JS
Dunlop
C I
CI
Allen
S L
SL
Demme
W C
WC
D000818:Animals; D019296:Capnography / Q000662:veterinary*; D002245:Carbon Dioxide / Q000032:analysis* / Q000097:blood; D004285:Dogs / Q000601:surgery*; D007385:Intermittent Positive-Pressure Ventilation / Q000662:veterinary*; D010313:Partial Pressure; D013908:Thoracotomy / Q000662:veterinary*; D013990:Tidal Volume
D002245:Carbon Dioxide